1. Field of the Invention
The present invention relates to a bulb socket and more particularly to a bulb socket for a wedge bulb used in, for instance, an automobile.
2. Prior Art
One of known bulb sockets is designed for retaining a wedge-base bulb therein. A wedge-base bulb generally includes a glass bulb that encloses a filament therein and a flat sealing element provided at the base of the glass bulb. A lead wire is led out from the base of the sealing element and disposed on the flat surface of the sealing element.
A bulb socket for this wedge-base bulb has a bulb retention portion for retaining the wedge-base bulb therein; and in this bulb retention portion, a conducting terminal is installed so that the conducting terminal is in contact with the lead wire and retains the sealing element of the bulb. The conducting terminal has a connector terminal; and a connector case is integrally formed with the bulb retention portion, thus forming, together with the connector terminal, a connector portion that is in the rear portion of the bulb socket.
A connector connected with a power source is coupled to the connector portion, so that the wedge-base bulb is connected to the power source via the conducting terminal.
The above-described conducting terminal is provided with an engagement piece that is formed in a cut-and-erected state. When the conducting terminal is inserted from the front end of the bulb retention portion, the engagement piece is engaged with an engagement step that is formed in the bulb retention portion. As a result, the conducting terminal is retained in the bulb retention portion.
In this prior art bulb socket, the engagement step is formed by a die that is pulled out toward an opposite side from the bulb retention portion. In other words, the die is pulled toward the connector portion so as to form the engagement step.
Since in the above-described conventional bulb socket the engagement step that is engaged with the engagement piece of the conducting terminal is formed by a die that is pulled out from the rear end of the connector portion, the engagement step is not visible from the outside. As a result, the engagement of the engagement piece of the conducting terminal and the engagement step is checked only by the feel of finger of an operator. This, however, causes reliability problems.
In addition, since the die for molding the engagement step is pulled toward the connector portion, a pull-out hole for pulling out the die is formed in a partition wall between the connector portion and the bulb retention portion. If the size of the bulb socket is reduced, an insert hole for the connector terminal formed in the partition wall overlaps with the pull-out hole for the die, or part of the side wall of the connector portion needs to be cut out so as to avoid the overlapping of the insert hole for the connector terminal and the pull-out hole for the die. This causes a problem. The shape of the connector portion is limited.
Accordingly, the object of the present invention is to provide a bulb socket that reliably retains a connection terminal therein and increases the degree of design choice.
The above object is accomplished by a unique structure for a bulb socket in which a pull-out hole for a die for molding an engagement step that extends substantially perpendicular to a direction in which a bulb is inserted is provided, and the pull-out hole is formed so as to penetrate the outer wall of a bulb retention portion of the bulb socket.
In the bulb socket of the present invention, the engagement step formed in the bulb socket can be seen from the outside through a window which is the pull-out hole. Accordingly, whether or not the engagement piece of a conducting terminal is engaged with the engagement step of the bulb socket can be easily determined through the window or the pull-out hole.
In addition, the die for molding the engagement step is pulled out in the direction nearly perpendicular to the direction in which the bulb is inserted in the bulb socket. Thus, no hole other than a terminal insert hole is formed in the partition wall between the bulb retention portion and the connector portion of the bulb socket, and the as a result design of the socket is not restricted.